Some backpacks are in particular for use in sports and leisure activities involving more or less pronounced motions of the arms obliquely to the direction of locomotion, in particular in the form of pendulum motion, for example in-line skating or skiing.
One such backpack is known, DE 296 15 828 U/U.S. Pat. No. 5,873,506. This backpack has an obliquely extending main shoulder strap with a lengthwise displaceable slide provided with two buckles to which the upper and lower portions of the other shoulder strap are alternatively fastenable.
The known backpack permits one- and double-sided wearing without faulty posture. Along with maximum freedom of movement it achieves a uniform weight distribution without cramping of cervical spine and back muscles and with relief of the spinal column.
However, the known backpack is not put on in the accustomed fashion by extending the arms through the two shoulder straps. One instead first draws the main shoulders strap over one's head and then fastens one or the other portion of the other shoulder strap alternatively to the slide. Use of the known backpack therefore requires instruction by expert personnel.